Figure 1.

OBP gene repertoire in the 12 Drosophila spp. Values on the right part indicate the number of putative functional genes and
pseudogenes (in parenthesis). Values in red indicate the inferred number of genes
at the ancestral nodes of the phylogenetic tree. Values above the branches show the
number of gene gains (gene duplications events), and below the branches X(Y) represent
the total number of losses (deletions plus pseudogenization events [X]) and pseudogenization
events (Y). OBP, odorant-binding protein.